Direct current electric power systems and method of operating the same

Abstract

A converter system includes a power converter including a first bridge circuit including at least one first switching device. The power converter also includes a second bridge circuit magnetically coupled to the first bridge circuit. The second bridge circuit includes at least one second switching device. The converter system also includes a plurality of first conductors of opposing polarities coupled to the first bridge circuit. The converter system further includes a plurality of second conductors of opposing polarities. At least one second conductor of the plurality of second conductors is coupled to the second bridge circuit. The converter system also includes a third conductor coupled to one first conductor of the plurality of first conductors and coupled to the second bridge circuit.

What is claimed is: 
     
       1. A converter system comprising:
 a power converter comprising:
 a first bridge circuit comprising at least one first switching device; 
 a second bridge circuit magnetically coupled to said first bridge circuit, said second bridge circuit comprising at least one second switching device; 
 a plurality of first conductors of opposing polarities coupled to said first bridge circuit; and 
 a plurality of second conductors of opposing polarities, wherein at least one second conductor of said plurality of second conductors is coupled to said second bridge circuit; and 
 
 a third conductor coupled to one first conductor of said plurality of first conductors and coupled to said second bridge circuit. 
 
     
     
       2. The converter system in accordance with  claim 1 , wherein said power converter is a bi-directional direct current (DC)-to-DC converter. 
     
     
       3. The converter system in accordance with  claim 1 , wherein said converter system is a bi-directional partial power bridge system configured to regulate power transmission therethrough by regulating phase shifting between said first bridge circuit and said second bridge circuit. 
     
     
       4. The converter system in accordance with  claim 3 , wherein said bi-directional partial power bridge system comprises one of a dual-active bridge topology, an H-bridge topology, a half-bridge topology, a single-ended primary-inductor topology, and a Ćuk topology. 
     
     
       5. The converter system in accordance with  claim 1  further comprising an isolation transformer, wherein said first bridge circuit and said second bridge circuit are magnetically coupled to each other through said isolation transformer. 
     
     
       6. The converter system in accordance with  claim 5  further comprising a resonant tank circuit coupled to said first bridge circuit and said isolation transformer. 
     
     
       7. The converter system in accordance with  claim 1  further comprising an output inductor coupled to said second bridge circuit. 
     
     
       8. The converter system in accordance with  claim 1 , wherein said power converter is configured to transmit a first current and said third conductor is configured to transmit a second current greater than the first current. 
     
     
       9. The converter system in accordance with  claim 1 , wherein said plurality of first conductors of opposing polarities comprises a first positive polarity conductor and said plurality of second conductors of opposing polarities comprises a second positive polarity conductor, said third conductor coupled to said first positive polarity conductor. 
     
     
       10. The converter system in accordance with  claim 9 , wherein said plurality of first conductors of opposing polarities further comprises a first negative polarity conductor and said plurality of second conductors of opposing polarities further comprises a second negative polarity conductor, said third conductor further coupled to said second negative polarity conductor. 
     
     
       11. The converter system in accordance with  claim 9 , wherein said third conductor is further coupled to said second positive polarity conductor. 
     
     
       12. The converter system in accordance with  claim 1 , wherein said plurality of first conductors of opposing polarities comprises a first negative polarity conductor and said plurality of second conductors of opposing polarities comprises a second negative polarity conductor, said third conductor coupled to said first negative polarity conductor. 
     
     
       13. The converter system in accordance with  claim 12 , wherein said plurality of first conductors of opposing polarities further comprises a first positive polarity conductor and said plurality of second conductors of opposing polarities further comprises a second positive polarity conductor, said third conductor further coupled to said second positive polarity conductor. 
     
     
       14. The converter system in accordance with  claim 12 , wherein said third conductor is further coupled to said second negative polarity conductor. 
     
     
       15. A direct current (DC) electrical power system comprising:
 a plurality of rechargeable DC storage devices; and 
 a plurality of DC-to-DC converter systems, each DC-to-DC converter system of said plurality of DC-to-DC converter systems coupled to a respective rechargeable DC storage device of said plurality of rechargeable DC storage devices, said each DC-to-DC converter system comprises:
 a DC-to-DC converter comprising:
 a first bridge circuit comprising at least one first switching device; 
 a second bridge circuit magnetically coupled to said first bridge circuit, said second bridge circuit comprising at least one second switching device; 
 a plurality of first conductors of opposing polarities coupled to said first bridge circuit; and 
 a plurality of second conductors of opposing polarities, wherein at least one second conductor of said plurality of second conductors is coupled to said second bridge circuit; and 
 
 a third conductor coupled to one first conductor of said plurality of first conductors and coupled to said second bridge circuit. 
 
 
     
     
       16. The DC electrical power system in accordance with  claim 15 , wherein said plurality of rechargeable DC storage devices comprises a plurality of rechargeable DC storage batteries. 
     
     
       17. The DC electrical power system in accordance with  claim 16 , wherein each rechargeable DC storage battery of said plurality of rechargeable DC storage batteries comprises a plurality of rechargeable electrochemical cells electrically isolated from each other. 
     
     
       18. The DC electrical power system in accordance with  claim 17 , wherein said plurality of rechargeable electrochemical cells are coupled electrically in at least one of series, parallel, and a combination of series and parallel. 
     
     
       19. The DC electrical power system in accordance with  claim 16 , wherein at least one rechargeable electrochemical cell of said plurality of rechargeable electrochemical cells is a sodium metal halide cell. 
     
     
       20. The DC electrical power system in accordance with  claim 16 , wherein a first portion of said plurality of rechargeable electrochemical cells has at least one characteristic rating value different from a characteristic rating value of a second portion of said plurality of rechargeable electrochemical cells. 
     
     
       21. The DC electrical power system in accordance with  claim 15  further comprising an isolation transformer and a resonant tank circuit, wherein:
 said first bridge circuit and said second bridge circuit are magnetically coupled to each other through said isolation transformer; and 
 said resonant tank circuit coupled to said first bridge circuit and said isolation transformer. 
 
     
     
       22. The DC electrical power system in accordance with  claim 15 , wherein said DC-to-DC converter is configured to transmit a first current and said third conductor is configured to transmit a second current greater than the first current. 
     
     
       23. A method of operating a direct current (DC) electrical power system, said method comprising:
 transmitting a first portion of electric power between a rechargeable DC storage battery and a DC bus through a DC-to-DC converter, the DC-to-DC converter including a first bridge circuit and a second bridge circuit magnetically coupled to the first bridge circuit, thereby converting the first portion of electric power; and 
 transmitting a second portion of electric power between a first electrically conductive element extending between the rechargeable DC storage battery and the first bridge circuit to the second bridge circuit through a second electrically conductive element, thereby augmenting the converted first portion of electric power with the non-converted second portion of electric power. 
 
     
     
       24. The method in accordance with  claim 23 , wherein transmitting a first portion of electric power and transmitting a second portion of electric power comprises bi-directional power transmission including one of discharging the rechargeable DC storage battery and recharging the rechargeable DC storage battery. 
     
     
       25. The method in accordance with  claim 23 , wherein the DC electrical power system includes a plurality of rechargeable DC storage batteries and a plurality of DC-to-DC converters, each rechargeable DC storage battery of the plurality of rechargeable DC storage batteries and each DC-to-DC converter of the plurality of DC-to-DC converters define a battery and power conversion string, said transmitting a first portion of electric power and transmitting a second portion of electric power comprises regulating voltage in a first a battery and power conversion string to a first voltage value and regulating voltage in a second battery and power conversion string to a second voltage value different from the first voltage value. 
     
     
       26. The method in accordance with  claim 23 , wherein the DC electrical power system includes a plurality of rechargeable DC storage batteries and a plurality of DC-to-DC converters, each rechargeable DC storage battery of the plurality of rechargeable DC storage batteries and each DC-to-DC converter of the plurality of DC-to-DC converters define a battery and power conversion string, said transmitting a first portion of electric power and transmitting a second portion of electric power comprises regulating current transmission in a first a battery and power conversion string to a first current value and regulating current transmission in a second battery and power conversion string to a second current value, the second current value one of substantially similar to and different from the first current value. 
     
     
       27. The method in accordance with  claim 23 , wherein the first bridge circuit includes a plurality of first switches and the second bridge circuit includes a plurality of second switches, wherein transmitting a first portion of electric power and transmitting a second portion of electric power comprises opening and holding open one of the plurality of first switches and the plurality of second switches and performing switching operations through one of the plurality of second switches and the plurality of first switches.